Underground storage tank



June 26, 1951 E. s. POMYKALA 2,558,580

UNDERGROUND STORAGE TANK Filed Jan. 23. 1945 Patented June 26, 1951 UNITED STATES-PATENT OFFICE UNDERGROUND s'ronAcE TANK y Edmund S. Pomykala, United States Navy Application January 2s, 1945, serial No. 574,147

This invention relates to improvements in underground tanks, particularly to tanks which are intended for storage of inflammable liquids such as gasoline, fuel oil or the like. More specifically, it has to do with novel forms and construction of these tanks, whereby great strength and resistance to bombing stresses are obtained with a great economy of material and labor.`

This tank falls in the general class of hydraulically prestressed tanks. The novelty in this tank is its form as `well as the mode of construction. The tank shown in drawing is circular in plan, being composed of two dome-like surfaces, one serving the base and the other the roof or ceiling. These two domed surfaces are connected by a continuous wall circular in plan, and a row or rows of columns flared on top and bottom. These columns being arranged along a circle or series of concentric circles. Generally in the present state of the art where storage tanks of considerable capacity are built, and diameters of tanks substantially increased, at ends have been used supported on a series of equally spaced structural steel columns arranged in a rectangular grid form, very similar to the familiar structural steel building construction. Such construction is not very economical in the use of material. One of the requisites of economical construction is a tank which is monolithic and where the various components act as one integral unit. It is also necessary to eliminate large variations of stresses in the shell. Underground tanks are also often built in soft ground. Here it is important that the distribution of pressure on the soil is nearly uniform, otherwise distortions will arise which may cause leaks. For smaller tanks plain domed ends would in general be satisfactory and no columns are necessary but for larger tanks and fairly shallow excavations, columns or other interior supports have to be used. If tank linings are prestressed hydraulically and the roof is supported by the contained water under pressure, if further the roof is restrained by columns as here shown, the lining, if elastic, would take on a shape approaching a flat dome. It would be similar to the shape taken by a flat surface of sheet rubber restrained by rigid and ared walls and columns and distended by water under pressure. Such surface would not have a uniform radius of curvature in all radial planes, but it would approach uniform curvature for small distending pressures.

In the theory of spherical, cylindrical or similar pressure vessels the stresses are carried on the periphery of the vessels, there being no other 1 Claim. (Cl. 'I2-14) supports. It may be shown, however, that if radial members are introduced distortion and therefore the stress in the skin or lining of the vessel is smaller. It is similar to the action of spokes in a wheel. In this tank the columns although not quite radial for practical reasons, approach that position because of the atness of curvature. This form incidentally has another advantage in that it minimizes bending moments from superimposed loads in the encased roof and base slabs.

This tank is sheet metal lined andconcrete encased with both components prestressed during construction by the contained water or other suitable liquid in the tank, while the casing is being `poured in place. The advantage of constructing tanks in this manner is that the concrete is generally always in compression, minute cracks are'eliminated andthe underlying plate lining is better preserved.

This design has other advantages. It is not only desirable to prestress the steel lining and the concrete casing, but it is necessary if economy of construction is to be secured, to bond the two materials intimately. When the sheet metal lining and concrete casing are well bonded, they act as an integral unit, verymuch like reinforcing rods and encasing concrete in reinforced concrete beams, arches or domes. One feature of this invention is the method of securing this bond. The invention also covers the steel plate lining and the superimposed reinforcing rods, with the sheet metal columns all welded together to form a very stiff truss-like frame. This framing, together with the contained water in the shell, resists the deforming forces of semi-liquid concrete, while it is being poured for the casing, obviating any necessity for internal bracing.

A further object is to so tie the two faces of concrete casing or tie the metal lining to reinforcing rods in the external face of the concrete casing that the whole is constructed similarly to a tied and trussed reinforced concrete beam, the trussing or diagonal members acting as shear reinforcing. In this manner greater roof or side loads can be carried by supporting roof slabs or side Walls for the same thickness of concrete.

Other and more specific objects will become apparent as the description of the details of this invention proceeds, having reference to the accompanying drawing. wherein:

Fig. 1 is a partial plan view, partly in section of one form of tank formed in accordance with the present invention.

Fig. 2 is a typical diametrical cross-section through the tank. The structure illustrated is composed of a vertical cylinder, wherein concrete domed roof I and dished bottom la are connected by a cylindrical wall 2 and columns 9.

Fig. 3 is a perspective view partly in section on a larger scale of the average construction of the shell and casings.

Fig. 4 is a vertical section on an enlarged scale oi' the average construction, showing the shell and the welded rods forming the frame or the caging.

In all views, numeral 3 indicates metallic sheet lining. This lining is continuous over the sides, bottom and roof and is joined to the lining encasing the columns indicated in the drawing by numeral 8. Metallic sheet lining 3 is attached rmly to the concrete by means of trussed rods 6 firmly welded to the sheet To these circumferential bent or trussed rods, crossed rods l and are welded in turn. The reinforcement shown is preferred but this arrangement may be varied if so desired. What is intended, however, is to make a. very rigid frame or selfsupporting structure, composed of the lining,

hollow columns, bent truss rods and a layer of crossed rods forming a network, all firmly welded together, forming a rigid truss-like cage.

The columns 9 equally spaced in a circle or series of circles concentric with the tank wall are surrounded with sheet metal 8 bonded to the enclosed concrete with metal clips 9a welded to the metal lining. The columns flare at top and bottom and are faired into the convex linings of the roof and bottom.

The access pit or service opening has concrete walls, l0. It may be made large enough to hold necessary pumps as desired. Preferably this pit shouldbe circular in plan. Numeral I I indicates a metal manhole cover, and numeral I2 indicates a surface pit cover, which may be made of 40 any suitable material.

Limited changes may be made in the arrangement of reinforcement or columns without departing from the spirit of the invention or the scope of the appended claim.

What is claimed is: l

An underground storage tank substantially in the form of a vertical cylinder with a convex top and bottom with a service opening at the top and having a plurality of inner vertical columns arranged in a circle concentric with the wall of the cylinder, said columns supporting the top, said tank comprising an inner cylindrical metal lining covering the wall of the tank, convex top and bottom metal linings integral with the cylindrical lining, cylindrical metal linings surrounding said vertical columns flared at the top and bottom, faired into the top and bottom linings and integral therewith, reinforcing elements mounted inside said column linings and integral therewith for keying into concrete, a network of metal reinforcing elements completely surrounding the outside of the tank lining and being welded to this lining, and a mass of concrete surrounding the entire metal lining of the tank, enclosing said reinforcing elements, filling the 1inings of said columns and forming a single monolithic unit. Y

EDMUND S. POMYKALA.

REFERENCES CITED The following references are of record in the ille of this patent:

UNITED STATES PATENTS Number Name Date 1,109,214 Featherstone i Sept. 1, 1914 1,497,142 Hart June l0, 1924 2,058,038 Schorer Oct. 20, 1936 2,080,879 Reed May 18, 1937 2,326,010 Crom- -i Aug. 3, 1943 2,355,947 Bondy et a1 Aug. l5, 1944 2,382,171 Pomykala Aug. 14, 1945 FOREIGN PA'I'ENTS Number Country Date 105,308 Australia 1938 

